The human endocannabinoid system (ECS) is a complex signalling network involved in many key physiological processes. The ECS includes the cannabinoid receptors, the endocannabinoid ligands, and the enzymes related to their synthesis and degradation. Other cannabinoids encompass the phytocannabinoids from Cannabis sativa L.(marijuana) and the synthetic cannabinoids. Alterations in the ECS are associated with different diseases, including inflammatory and immune-mediated disorders such as allergy. Allergy is a global health problem of increasing prevalence with high socio-economic impact. Different studies have convincingly demonstrated that cannabinoids play a role in allergy, but their actual contribution is still controversial. It has been shown that cannabinoids exert anti-inflammatory properties in the airways and the skin of allergic patients. Other studies reported that cannabinoids might exacerbate asthma and atopic dermatitis mainly depending on CB2-mediated signalling pathways. A better understanding of the molecular mechanisms involved in the mode of action of specific cannabinoids and cannabinoid receptors on relevant immune cells under different biological contexts might well contribute to the design of novel strategies for the prevention and treatment of allergic diseases. Future research in this promising emerging field in the context of allergy is warranted for the upcoming years.
